High efficiency multiplexing scheme for multi-channel A/D conversion

Multiplexing technique is frequently used in multichannel analog to digital (A/D) conversion, thus reducing the system complexity and cost. However, if the sampling frequencies of the input channels are not equal, obtaining high A/D converter utilization is rather complicated. A new rule-based synchronous multiplexing scheme for multi-channel A/D conversion with different channel sampling frequencies is proposed. It is optimal in the sense that the required A/D conversion frequency is a minimum. The channel sequencing is based on the earliest deadline principle, similar to the one used in real-time dynamic scheduling algorithms.